This paper analyses the principle of seal, the fault of leakage and the cause of fault to the sealing arrangement for upper bearing unit in SJ 2000 oil purifier, and gives the means of improvement.

• 此文分析了 SJ2000型分油机上部轴承密封装置的密封机理、漏油故障及故障产生的原因，并提出了改进的方法。